Tin Whiskers

I think it's cool when a little bit of novel science or technology presents itself unpredictedly.  The Mandelbrot set was like that.  Tin whiskers are like that.  In response to environmental and health guidelines under the RoHS (restriction of hazardous substances) initiatives, the mix of metals in electronic solder has been changed to eliminate lead.  Electronic solder has had tin it for as long as I can remember.  However, the amount of tin has been increased and the mix has changed, and this has highlighted a behavior of tin alloys.

Tin spontaneously grows whiskers over time.  These can be 10 mm long.  In electronic equipment, a whisker can reach out and cause an electrical short.  The short can be permanent, transient (as the whisker melts), or destructive (as the whisker vaporizes and takes some of the surroundings with it).  Other metals, including zinc, can also grow whiskers.  See Nasa Goddard site.

This is a picture of my block of tin.  I bought is along with some zinc and bismuth (to make crystals).  No whiskers yet... The metal came in the US Mail.  It was a heavy box. For this purchase, they changed the advertising slogan from "If it fits, it ships", to "What the hell you got in here!?"